氧化锌分级结构的制备及在染料敏化太阳能电池中的应用

发布时间：2018-05-18 15:21

本文选题：染料敏化太阳能电池 + 光阳极　；参考：《华侨大学》2014年硕士论文

【摘要】：当前，全球正面临着日益严峻的能源枯竭和环境污染问题。开发利用新能源特别是储量丰富、安全绿色的太阳能逐渐成为人们的聚焦点。染料敏化太阳能电池（dye-sensitized solar cell，DSSC）借鉴绿色植物光合作用的原理，自诞生以来一直备受瞩目。作为一种新颖的太阳能转换装置，其组装简单、制作方便、成本低，一度成为人们研究的热点。作为电池的核心部件，光阳极在光电过程中的电荷收集和传送方面起着关键作用。其中，应用效果最好的光阳极材料为TiO2。在众多宽带隙的半导体氧化物中，ZnO的禁带宽度与TiO2最为接近并且ZnO的电子迁移率和电子扩散系数均高于TiO2，非常有潜力应用在DSSC领域。近年来，ZnO在DSSC中的应用研究取得了一定的进展。考虑到ZnO零维、一维和二维结构在光散射和比表面积方面的不足，本文尝试制备ZnO的三维分级结构光阳极，增大比表面积的同时实现对入射光的有效捕获和散射，以充分利用入射光，达到提高电池效率的目的。主要研究内容如下：（1）采用水热法合成基于一维ZnO纳米棒的分级结构，系统探索制备条件如水热温度、pH值和反应时间对产物形貌及DSSC光电性能的影响。实验结果表明在反应溶液pH为10和温度为120°C的条件下水热18h后所得ZnO光阳极薄膜组装的DSSC相对表现出最好的光电性能。由于该条件下制备的ZnO纳米棒基分级结构在染料吸附、电子传输和光线捕获上的优势，其DSSC的短路电流密度达到7.29mA·cm-2，光电效率达到2.42%。（2）采用水热法合成基于二维ZnO纳米片的分级结构，，研究了反应物摩尔比对产物形貌的影响。结果表明ZnO纳米片基球状分级结构（ZnO-MS）具有较大的比表面积、孔径和孔容以利于吸附更多的染料、较优异的光散射性能和相对低的电荷复合率，从而表现出较好的光电性能。采用钛酸四正丁酯的乙醇溶液90°C热浴浸泡处理ZnO-MS光阳极，DSSC性能获得提升：短路电流密度为6.65mA·cm-2、开路电压为0.676V、效率达2.94%，分别比没有经过后处理的纯ZnO-MS-DSSC提高了44.9%、12.5%和67.0%。（3）采用水热法合成基于零维ZnO纳米粒的分级结构，表征结果显示该产物产量大、结晶度高且形貌规整。漫反射和染料吸附量测算表明ZnO纳米粒基分级结构（ZnO-HS）均优于商用ZnO纳米颗粒（ZnO-NP）。把ZnO-HS用作反射层材料应用在ZnO-NP和TiO2纳米颗粒（TiO2-NP）薄膜DSSC上，研究表明：添加反射层后光阳极的漫反射能力显著增强。ZnO-NP-DSSC的短路电流密度从5.47mA·cm-2提高到ZnO-NP/ZnO-HS-DSSC的12.6mA·cm-2，光电效率从原来的1.68%提高到3.40%。相反，尽管TiO2-NP-DSSC添加反射层后光阳极的漫反射能力得到增强，但是，TiO2-NP/ZnO-HS-DSSC的短路电流密度和效率均发生衰减，这个结果与TiO2-NP/ZnO-HS-DSSC内部的电荷复合有关，并在电化学阻抗图谱测试结果中得到了证明。
[Abstract]:At present, the world is facing increasingly serious problems of energy depletion and environmental pollution. Development and utilization of new energy, especially rich in reserves, safe and green solar energy has gradually become the focus of people. Dye-sensitized solar cells (DSCs) have been attracting much attention since their birth for reference to the principle of green plant photosynthesis. As a novel solar energy conversion device, it is easy to assemble, easy to manufacture and low cost. As the core component of battery, photoanode plays a key role in charge collection and transmission in photovoltaic process. Among them, the photoanode material with the best application effect is TIO _ 2. Among the wide band gap semiconductor oxides, the band gap width of ZnO is the closest to that of TiO2, and the electron mobility and electron diffusion coefficient of ZnO are higher than that of TIO _ 2, so it has great potential to be used in the field of DSSC. In recent years, some progress has been made in the application of DSSC. Considering the deficiency of ZnO zero-dimensional, one-dimensional and two-dimensional structure in light scattering and specific surface area, this paper attempts to fabricate the three-dimensional graded structure photoanode of ZnO, which increases the specific surface area and realizes the effective capture and scattering of incident light at the same time. In order to make full use of the incident light, the efficiency of the battery can be improved. The main contents of the study are as follows: 1) the hierarchical structure based on one-dimensional ZnO nanorods was synthesized by hydrothermal method. The effects of preparation conditions such as hydrothermal temperature, pH value and reaction time on the morphology and optoelectronic properties of DSSC were systematically explored. The experimental results show that the DSSC assembled by ZnO photoanode films after 18 hours of heat treatment at pH 10 and 120 掳C shows the best optoelectronic properties. Because of the advantages of the ZnO nanorods in dye adsorption, electron transport and light capture, the short-circuit current density of DSSC is up to 7.29mA cm-2, and the optoelectronic efficiency is 2.42. The effects of molar ratio of reactants on the morphology of the products were studied. The results show that ZnO nanoparticles have large surface area, pore size and pore volume for adsorption of more dyes, excellent light scattering performance and relatively low charge recombination rate, thus showing better photoelectric performance. The performance of ZnO-MS photoanode was improved by immersion in 90 掳C ethanol solution of tetrabutyl titanate in 90 掳C hot bath. The short-circuit current density was 6.65mA cm-2, the open circuit voltage was 0.676 V, and the efficiency was 2.94, which was higher than that of pure ZnO-MS-DSSC without post-treatment by 44.9% and 67.0%, respectively. The gradation structure based on zero-dimensional ZnO nanoparticles was synthesized by hydrothermal method. The characterization results showed that the product had high yield, high crystallinity and regular morphology. The results of diffuse reflectance and dye adsorption showed that ZnO nanoparticles were superior to commercial ZnO nanoparticles in the structure of ZnO-HSs. ZnO-HS was used as a reflective layer material on ZnO-NP and TiO2 nanocrystalline TIO _ 2-NPN film DSSC. The results show that the diffuse reflectance of the photoanode increases from 5.47mA cm-2 to 12.6mA cm-2 of ZnO-NP/ZnO-HS-DSSC, and the photoelectric efficiency increases from 1.68% to 3.40%. On the contrary, although the diffuse reflectivity of the photoanode increases with the addition of a reflection layer in TiO2-NP-DSSC, the short-circuit current density and efficiency of TiO2-NP- / ZnO-HS-DSSC decrease, which is related to the charge recombination inside the TiO2-NP/ZnO-HS-DSSC. The results of electrochemical impedance spectra are proved.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TQ132.41;TM914.4

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